Analyzing devices, used to determine the blood alcohol content of those about to drive vehicles, are commonly available. They emanated from breathalyzers used by law enforcement to test whether or not a driver was intoxicated, i.e., over the legal limit. In more recent times this traditional use of breathalyzing devices has been enhanced by combining a breathalyzer and an ignition locking system to prevent known, problem intoxicated drivers from being able to start their vehicle. This has been used with habitual violators in order to allow driving for necessary reasons, for example, to work, after confirming they are not intoxicated.
Typically at random times after the engine has been started the ignition interlock device will require another breath sample. The purpose of this is to prevent a friend (imposter) from breathing into the device to pass the test, thus enabling the intoxicated person to get behind the wheel and then drive away. If the breath sample isn't provided, or the sample given exceeds the ignition's interlock set blood alcohol level, the device will log the event, warn the driver, send a command station warning and begin visible and auditory warnings such as lights flashing, horn honking, etc.
Modern ignition interlock devices use an ethanol specific fuel cell for a sensor. A fuel cell is an electrochemical device in which alcohol undergoes a chemical oxidation reaction at a catalytic electrode surface (often platinum) to generate an electrical current. This current is then measured and converted to an alcohol equivalent rating. If it exceeds safe limits, warnings are issued.
A device log keeps a record of the activity on the device in the interlock vehicle electrical system. This record, or log, is printed out or downloaded each time the device sensors are calibrated, commonly at 30, 60 or 90 day intervals. Authorities may even require periodic review of the log. If violations are detected, then additional sanctions can be implemented. The typical periodic calibrations performed use either a pressurized alcohol/gas mixture at known standard alcohol concentration to test accuracy, or an alcohol wet bath (Guth) arrangement that contains a known standard alcohol solution. Cost of installation, maintenance and calibration are generally paid by the offender, which typically can run $100 a month or more.
A breath alcohol ignition interlock device is typically comprised of two components. One is a handheld component that contains the fuel cell to contain the electrochemical reaction and response after gathering the initial breath data. The second component is a relay box that relays the information and data from the first hand held unit to a command station or to provide a warning alarm, such as lights flashing, horn honking, etc or both. Both parts of the device offer opportunities for mischief, if one is inclined to try and beat the device and forestall court penalty sanctions, etc. Put another way, for the devious user on whom courts have already imposed enforced use of an ignition interlock device, often there is a “match of wits” between the ignition interlock device manufacturer and the user.
Some obvious attempts at avoiding the consequences of use of an ignition interlock device include imposter fraud, i.e., someone else other than the intoxicated driver provides the breath sample or no breath sample at all, but simply use of stored fresh air. A third and perhaps more daring and reckless attempt by one under the influence is deactivation, simply by attempts at disconnecting or even destruction. A fourth and perhaps a more subtle evidentiary way of avoiding the consequences of detection of excess use of alcohol is simply to deny the accuracy of the device, i.e., a fuel cell that has gone “haywire”.
Manufacturers have done some things over the years to try and eliminate the risk of each of these avoidance techniques. For example, co-owned and commonly assigned application of some of these current inventors is U.S. Pat. No. 5,426,415 issued Jun. 20, 1995, is a breath temperature sensor to measure temperature of the breath sample to ensure that is the same temperature as normal human breath, thereby avoiding use of other non-human air sources. The '415 patent also requires rolling retests to ensure that the driver is the one that was tested and remains sober. U.S. Pat. No. 6,748,792 relates to use of video camera surveillance to capture the identity of the person being tested. U.S. Pat. No. 6,026,674 teaches use of detectors to detect use of alcohol removing filter media, such as activated charcoal by detecting the resultant low pressure caused by the pressure drop across an alcohol filter.
From the above it can be seen there are many “wily ways” of seeking to circumvent a breath alcohol ignition interlock device. A reliable interlock device avoids as many of these as possible, and detects the fraud, sending a signal to a command station, etc. That is, a good interlock device records attempts to physically tamper with it, detects circumvention or retest fraud attempts including disconnect efforts, and reports non-human air samples or attempts to filter out the breath, or mask the amount of alcohol blown into the device, and finally records and logs for evidentiary purposes each use.
One of the properties associated with high integrity breath alcohol ignition interlock devices is a need for proof of calibration. Calibration is expensive, and depending on the device, it needs to occur every 30, 60 or 90 days. Calibration usually involves the wet chemistry of known standards or a Guth bath. While necessary problems with calibration involve time consumption, expense of distant travel that may be necessary, inconvenience discourages expense and the travel to maintain integrity and the user's knowledge that lack of an adequately calibrated machine may make the evidence it collects inadmissible in court discourages this effort. One way all of this could be avoided is to develop a machine that self calibrates. That is to say, it internally reports information that could be used as States evidence that it is constantly calibrated. This would save money, time and expense of all concerned.
Yet another problem with alcohol ignition interlock devices is constant user circumvention by imposter fraud. As mentioned, there is a variety of existing state-of-the-art techniques that have been used to detect such fraud and also to detect artificial samples. Some detectors that are used detect attempts to filter out alcohol from the breath; others take a video of the person blowing into the breathalyzer. With the latter, this can be avoided by one person blowing into the breathalyzer and then a different person driving. A circumvention frustration technique that is used by this invention is using two video cameras, one to detect the person blowing into the breathalyzer and a second to detect the person driving. If different people are recorded on these two different videos, the system senses and keeps a video record of this. As far as the present Applicants know, no one has so far used two video cameras, one focusing on the person taking the test and the other focusing on the driver, in order to be sure they are the same.
Another device useful for the present invention to detect circumvention efforts is the use of an accelerometer both in the handheld unit and in the relay box to immediately sense attempts at destruction and send a warning to a command station that such activity is occurring. If desired, this may even be coupled with a GPS to report location.
While most circumvention detection systems focus on the handheld unit, this invention also makes use of detection systems on the relay unit. Therefore it even further frustrates circumvention efforts. In particular, it also uses an internal cell phone which calls back to a command station when there is a sobriety violation and it may use a wireless link (RFID technology) between the handheld unit and the relay box in order to avoid circumvention efforts by wire cutting.
Accordingly, it is a primary object of the present invention to provide a self calibrating breath alcohol ignition interlock device.
Another important objective as seen from the above discussion is to provide a unit with enhanced ability to detect circumvention efforts such as imposter fraud, artificial air sample, deviation by destruction, etc.
The invention features of novelty which characterize it are pointed out with particularity in the claims which form a part of this disclosure. For a better understanding of the invention, its operating advantages and how its specific objects are achieved, reference is made to the accompanying drawings and the descriptive matter in which preferred embodiments of the invention are illustrated. It is to be understood that all of these features need not be used in the same unit, and that improvements in existing devices may be achieved by any one of the additional advantageous or improvements described herein for either the handheld unit or the relay box used alone or in combination.